Treatment of aromatic hydrocarbons



Patented June 11, 1946 TREATMENT OF AROMA'IIC HYDRO CARBON S Louis Schmerling, Riverside, 111., and Ar-thur M. Durinski, Monroe, La., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Original application May 19, 1941,

Serial No. 394,166. Divided and this application August 7, 1944, Serial No. 548,506

This application .is a divisional application of our copending application Serial No. 394,166 filed May 19, 1941, now U. S. Patent No. 2,364,762, issued December 12, 1944.

This invention relates to the treatment of aromatic hydrocarbons to produce therefrom alkylated aromatic hydrocarbons. More specifically the process is concerned with the interaction of an aromatic hydrocarbon and an alkyd or aralkyl halide to produce mono-alkylated and polyalkylated aromatic hydrocarbons.

It is recognized that benzene has been converted into alkylated benzenes by treatment with an alkyl chloride in the presence of aluminum chloride. This reaction has the disadvantage that complex addition compounds are formed apparently involving the aluminum chloride and thus producing sludge-like materials which decrease the life of the aluminum chloride and interfere with continuous operation of the process. The present invention diiferentiates from the prior art on this subject in that the aromatic hydrocarbon and alkyl halide, this term being herein used broadly to include both alkyl and 'aralkyl halides, are caused to interact in the presence of a reactor packing material as hereinafter described. or

In one specific embodiment, the present invention comprises a process for producing alkylated aromatic hydrocarbons which includes contacting an aromatic hydrocarbon with an alkyl halide 12 Claims. (01. 260-671) n the presence of a catalyst comprising silica under alkylating conditions of temperature and pressure.

Aromatic hydrocarbons, such as benzene. toluene, other alkylated benzenes, naphthalene, al-

kylated naphthalenes, other polynuclear aromatics, etc, which are alkylated by alkyl halides as hereinafter set forth, may be obtained by the distillation of coal, by the. dehydrogenation and cyclization of aliphatic hydrocarbons and of alkylated aromatic hydrocarbons, and by other means.

Alkylating agents suitable for use according to the process of the present invention comprise alkyl halides including particularltchlorides, bromides, and fluorides. Typical alkyl chlorides comprise the methyl, ethyl, propyl, and isopropyl compounds as well as various butyl, pentyl, and higher alkyl derivatives. Aralkyl halides, of which benzyl chloride is typical, are also utilizloclty of this reaction is increased by the presence within the reactor of a catalyst comprising silica.

Alkylation of aromatic hydrocarbons of the types hereinabove set forth are also carried out in the presence or hydrogen or 02 a hydrogencontaining gas. There is relatively little formation of carbon and heavy hydrocarbonaceous material'upon the reactor packing material when these conversion reactions are carried out under hydrogen pressure, but carbon formation does occur to a substantial extent in the absence of added hydrogen.

In efiecting reaction between benzene or another aromatic bydrocarbon and an alkyl halide according to the process of the present invention, the exact method of procedure varies with the nature of the reacting constituents as well as with the composition of the reactor packing material, the presence of which accelerates the alkylation reaction. A simple procedure which is used in alkylating benzene consists in contacting a mixture of benzene and an alkyl chloride, such as isopropyl chloride, with silica gel at a temperature of from about 100 to about 500 C. and preferably from about 200 to about 400 C. under a pressure of from substantially atmospheric to approximately 200 atmosphere; or more. Intimate contact of the reacting components is effected by passing the reaction mixture over a fixed bed of the silica or the reacting components may be mixed in the presence of finely powdered silica. The reaction mixture undergoing treatment preferably contains between about 1 and about '20 molecular proportions of aromatic hydrocarbon per 1 molecular proportion of alkyl halide in order to diminish production of vpoly-alkylated hydrocarbons and to favor the production of the mono-alkylated aromatic compounds. Thus benzene and ethyl chloride or isopropyl chloride are commingled and passed through a reactor containing'a granular material containing granular silica, or at least a portion of the benzene is charged to a reactor while the alkyl halide as such or preferably diluted by anable as alkylating agents for aromatic hydrocarbons.

While the alkylatlon reaction occurs readily in the absence of added catalytic material, the veother portion of the benzene being treated, is in-' troduced at various points between the inlet and the outlet of the reaction zone in such a way that the mixture imdergoing reaction will at all times contain a relatively low proportion of alk'yl chloride and thus favor the production of monoalkylated benzene rather than the formation of 'more-highly alkylated benzenes.

Hydrogen chloride formed during the alkylation of an aromatic hydrocarbon by an alkyl halide is recovered as a valuable by-product which 3 may be utilized for any other purpose as desired or a portion of said hydrogen chloride may be commingled with the reactants charged to the process.

-While the method of passing an alkyl halide and benzene or another aromatic hydrocarbon, either together or counter-currently, through a suitable reactor under suitable conditions'oftemperature and pressure in the presence of added granular packing material is the generally preferred procedure, the interaction of an alkyl halide and an aromatic hydrocarbon may also-be efiected in batch type operation utilizing a closed vessel in which some or the reacting constituents are in liquid phase and are maintained in intimate contact by some means of agitation. The

choice of operating procedure is dependent upon such circumstances as the temperature and presadditional quantities of the mixture of alkyl' halide and aromatic hydrocarbon being charged to reaction. Thus the .alkylated aromatic hydrocarbons may be substantially freed from the excess of the originally charged aromatic hydrocarbon and then be separated into desired fractions or individual compounds by distillation at ordinary or reduced pressure or by other suitable means.

The following examples are given to illustrate the character of results obtained by the use of the present process, although the data presented limiting the generally broad scope of the invention.

EXAMPLE I A mixture of 80 parts by weight of benzene, 40 parts by weight of isopropyl chloride, and parts by weight of 3-8 mesh silica gel was placed in an autoclave, hydrogen was added thereto to a total pressure of 100 atmospheres, and the resulting mixture was heated for ihours at the temperatures indicated and with the results shown in the following table:

Tabla-Alkyloiton of benzene with isopropyl chloride rm the presence of silica gel- Glass-lined autoclave autoclave liner of glass equip ed 'mize eontaet o reaction mixture with. the steel walls of the autoclave.

i No hydrogen added.

I In the absence of added silica gel otherwise identical reaction mixtures treated at 150 C.

yielded 4 parts by weight of mono-isopropyl benzene and 2 parts by weight of higher boiling maare not introduced with the intention of unduly trial, while at 250 0., like reaction mixtures of benzene and isopropyl chloride yielded 10 parts by weight of mono isopropyl benzene, 8 parts by weight of di-isopropyl benzene, and 6 parts by weight of higher boiling material.

The above results show that silica gel catalyzed the condensation of benzene with isopropyl chloride at temperatures as low as 150 and 200 C. Better yields were obtained when no capillary stopper was used on the glass liner of the autoclave, these results indicating that even in the presence of silica gel better results were obtained if the reactants could also come in contact with the steel walls of the autoclave. In run #5, alkylation occurred also at 200 C. under a,relatively lowpressure in they absence of added hydrogen but in the presence of silica gel.

EXAMPLE II 80 parts by weight of benzene, 25 parts by weight of methyl chloride, and 10 parts by weight of a synthetically prepared silica-alumina-zirconia catalyst were placed in a rotating autoclave under an initial nitrogen pressure of 30 atmospheres and then heated for 4 hours at 300 C. under a maximum pressure of 110 atmospheres. The catalyst used was a synthetically prepared material formed by compositing 100 molecular proportions of hydrated silica, 2 molecular proportions of hydrated alumina, and 5 molecular.

proportions of hydrated zirconia, washing the composite until substantially free from alkali metal compounds, drying the resulting precipitated material and then grinding said material, mixing it with 4% by weight of flour and 2% by weight of stearic acid to form a composite suitable for forming into pelle by a pelleting machine. The formed pellets were then calcined in air to remove the flour and stearic acid.

At the end of the reaction the autoclave was cooled and85 parts by weight of yellow liquid and 12 parts by weight of black catalyst pellets were removed therefrom. The liquid product was found to contain 6 parts by weight of toluene, and

I 4.5 parts byweight of Xylenes and more-highly methylated benzene. The toluene was identified by preparation of 2,4-di-nitrotoluene with a melting point of C.

The nature of the present invention and its commercial utility can be seen from the specification and examples given, although neither section is intended to limit its generally broad scope.

We claim as our invention:

1. A process for producing a substantial yield of mono-alkylated benzene which comprises contacting from about 1 to about 20 molecular proportions of benzene with one molecular proportion of an alkylating agent consisting essentially of an alkyl chloride at a temperature from about to 500 C., under a pressure of iroxn substantially atmospheric to approximately 200 atmospheres, in the preoence ot'an 'alkylating catalyst consisting of silica. g

2. A process for producing a substantial yield of mono-alkylated benzene which comprises contacting from about 1 to about 20 molecular prowith glass stop er containing capillary designed to m ni-- portions of benzene with one molecular proportion of an alkylating agent consisting essentially of an alkyl bromide at a temperature of from about 100 to about 500 (2., under a pressure of from substantially atmospheric to approximately 200 atmospheres. in the presence or an alkyla catalyst-consistins of silica.

3. A process for producing a substantial yield oi mono-elkyloteo ben which comprises contacting from about 1 to about 20 molecular pro- P rtions of benzene with one moleculor proportion oi an alizylsting agent consisting essentially of on alkyl helicle at a temperature from about 100 to about 560 C., under a pressure of from substuntiully atmospheric to approximately 200 otmospheres, in thepresence of hydrogen sud oi on elkylatins estolyst consisting of silica.

i. A process for producing ethylbenoene which.

comprises contecting irom about i to shout to molecular proportions or benzene with one mos. A process ior producing o butyl benzene leculur proportion oi on olkylotine ogent consistim essentially oi'en isopropyl holide ot a. temperuture or irom shout lilO" to about 500 C., under o pressure or from substsiutlolly uospheric to opproxitely Zilil atmospheres in the presence oiorosen under on ullryletins cotolyst consist ins oi silico.

7. ll. process for producing on elmieteci terr zerie which comprises contcctiog irom stout in to about 220 molecular proportions oi benzene with 1 molecular proportion of an alkylatinz agent consisting essentially of an alkyl halide at a temperature of from about 100 to about 500? C.,

under a pressure of from substantially atmospheric to approximately 200 atmospheres, in the presence 0! an alkylating catalyst consisting of silica.

s. A process for producing slkylateri srtics which comprises subjecting a mono-heio-slksne and a molecular excess or an aromatic hydrocorbon to reaction under slkylating conditions and in the presence of o solicl slkyletins cotolyst con-- sisting of silico.

t. it process for producing elliyloteol uromstlcs which comprises suiojec s mono-liolo-olne end or molecular excess oi on sromutic hytirocoricon to reoction st on olmleting temperature of I from shout 100 (C. to about sec" 0.. cl in the presence of a solioi sliryluting cstslyst consisting" of silico.

it. A process for producing slstecl uromstics which comprisessulolecting on elmluting scent, consisting essentiully or on slkyl holicie, cool e molecular excess oi on uromstic hydrocarbon to reaction under olotins conditions sod is the presence or as solid elotiug cotolyst consisting of silica.

ii. A process for prorlucins sllrylsteo oromstics which comprises sulrlectins on oikylstiug scent, consisting essentially of on sllzyl heliole, one o molecule:- excess of on eromutic hydrocarbon to reaction st on ollsyletins temperature oi from about 100 C. to shout 500 C. and in the presence of e. solid ollsyloting cotollyst consisting of silics.

12. The process so defined in cloim ll further characterized in thot soiol ellsi'l heliue is s mono chloro-ollceue more 1 1 so so.

mom. 

